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Mirrors > Home > ILE Home > Th. List > 2onn | Unicode version |
Description: The ordinal 2 is a natural number. (Contributed by NM, 28-Sep-2004.) |
Ref | Expression |
---|---|
2onn |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | df-2o 6314 | . 2 | |
2 | 1onn 6416 | . . 3 | |
3 | peano2 4509 | . . 3 | |
4 | 2, 3 | ax-mp 5 | . 2 |
5 | 1, 4 | eqeltri 2212 | 1 |
Colors of variables: wff set class |
Syntax hints: wcel 1480 csuc 4287 com 4504 c1o 6306 c2o 6307 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 105 ax-ia2 106 ax-ia3 107 ax-in1 603 ax-in2 604 ax-io 698 ax-5 1423 ax-7 1424 ax-gen 1425 ax-ie1 1469 ax-ie2 1470 ax-8 1482 ax-10 1483 ax-11 1484 ax-i12 1485 ax-bndl 1486 ax-4 1487 ax-13 1491 ax-14 1492 ax-17 1506 ax-i9 1510 ax-ial 1514 ax-i5r 1515 ax-ext 2121 ax-sep 4046 ax-nul 4054 ax-pow 4098 ax-pr 4131 ax-un 4355 |
This theorem depends on definitions: df-bi 116 df-3an 964 df-tru 1334 df-nf 1437 df-sb 1736 df-clab 2126 df-cleq 2132 df-clel 2135 df-nfc 2270 df-ral 2421 df-rex 2422 df-v 2688 df-dif 3073 df-un 3075 df-in 3077 df-ss 3084 df-nul 3364 df-pw 3512 df-sn 3533 df-pr 3534 df-uni 3737 df-int 3772 df-suc 4293 df-iom 4505 df-1o 6313 df-2o 6314 |
This theorem is referenced by: 3onn 6418 nn2m 6422 isomnimap 7009 enomnilem 7010 fodjuf 7017 infnninf 7022 nnnninf 7023 ismkvmap 7028 ismkvnex 7029 exmidonfinlem 7049 exmidfodomrlemr 7058 exmidfodomrlemrALT 7059 prarloclemarch2 7227 nq02m 7273 prarloclemlt 7301 prarloclemlo 7302 prarloclem3 7305 prarloclemn 7307 prarloclem5 7308 prarloclemcalc 7310 hash3 10559 unct 11954 pwle2 13193 pwf1oexmid 13194 subctctexmid 13196 0nninf 13197 nnsf 13199 nninfex 13205 nninfsellemdc 13206 nninfself 13209 nninffeq 13216 isomninnlem 13225 |
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